1. Field of the Invention
The present invention relates to a recording and reproduction apparatus and method, and a disk. More particularly, the present invention relates to a recording and reproduction apparatus and method, and a disk, in which thermal stress is prevented from accumulating on a recording medium when data is repeatedly recorded on a disk.
2. Description of the Related Art
A conventional recording apparatus records data by modulating the intensity of a laser beam on the basis of data to be recorded and radiating it onto a disk, and causing a physical change in a recording medium.
In such conventional recording apparatuses, data is recorded on the basis of address information prerecorded on a disk. Therefore, when data is recorded with specific address information being specified, the area where the data is recorded is predetermined on the disk.
For example, it is known in a rewritable-type disk that, when a recording laser beam is repeatedly radiated onto the same area, thermal stress is accumulated on a recording medium. As a result, accurately recording data becomes difficult.
When data is recorded on a disk, it is necessary to record a signal for synchronization (hereinafter abbreviated as a synchronization signal) together with the data to be recorded in order to synchronize signals during reproduction. Since information (content) in such a synchronization signal is often determined according to the position (address) on the disk, a specific synchronization signal is provided for a predetermined address.
Therefore, when data is repeatedly recorded (overwritten) on a rewritable-type disk, the same synchronization signal is repeatedly written on the same portion of the disk. As a result, there is a problem in that thermal stress accumulates on that portion of the recording medium, and it becomes difficult to accurately reproduce a synchronization signal.
Accordingly, in order to solve such problems, a recording method for randomly changing the recording start point of recording data is disclosed in Japanese Patent Publication No. 8-10489. However, such a method has problems in that since data recorded on a disk is noncontinuous, it is difficult to provide recording timing during recording.